TTrawlersrawlers

trawler is a vessel that drags a funnel-shaped ramp on the stern. Older trawlers without inclined net through water to harvest fish or . ramps haul their nets over the sides using a haul line AThe net is wide at the mouth and tapers back to and a block on an overhead boom to bring in the cod a narrow cod end that collects the catch. The average end of the net. bottom trawl opening is 40 to 60 feet wide and 8 to 10 feet tall. Bottom trawlers usually tow their nets at 1 to Bottom trawlers 2 knots on or above the ocean floor. Fishermen might Bottom trawlers tow the net along the ocean floor to tow midwater trawls faster to catch faster-swimming catch fish that live on or just off the bottom. These schooling fish. fish include rockfish, cod, sablefish (black cod), ocean Trawlers have a large metal trawl door that is at- perch, flounder, and sole. Trawls can be designed to tached to each side, or wing, on the front of the net. catch particular groups of fish. A large mesh net (4 1/2 The water hits the doors and the pressure of the water inches to 5 inches) is kept on a stern-mounted reel. The passing over the door spreads the net open. The doors two doors are stored along the rails near the reel. are flat, oval, or slightly v-shaped. A steel cable extends The net is set off the stern by unwinding the reel so from the door to a winch just behind the pilot house. that the cod end is put into the water first. The rest of Most large trawlers have square the net is unrolled from the reel, and then the doors are sterns with inclined placed in the water. Water pressure on the doors causes ramps and are the doors to separate and open the net. Enough cable is referred to as then released to place the net at the desired depth. The stern trawl- upper lip of the net is lifted up by floats ers. The nets Boom Bottom dragger on the headrope while the lower lip of are hauled the net is pulled down by a weighted aboard up footrope. This action opens the net the inclined vertically.

Haul line Hold Reel with trawl

Winch Bottom trawler in operation

Checker

Door Headrope

Net Cod end Footrope Tow cable

Door

Getting to Know Oren go ’s Commercial Dover sole shrimpers Pacific pink shrimp are smaller than gulf shrimp and are sometimes called popcorn or cocktail shrimp or, mistakenly, bay shrimp. They have a three- to four-year life cycle. Shrimp live at depths of 40 to 150 fathoms in green or gray mud. Shrimpers, who fish from April 1 through October 1 31, tow one or two small-meshed (1 /2-inch) nets just above the ocean floor for small, pink cocktail shrimp. Single-rigged shrimpers Rubber discs may be attached to the net to hold it tow one net off the stern, Pacific pink shrimp down. There are now restrictions on the size of the like bottom draggers, rubber discs that can be used on footropes when trawl- and store the net on a ing on the Oregon continental shelf. These restrictions stern-mounted reel. confine trawling to mostly smooth bottoms, such as Double-rigged shrimp- sand and mud. Tow times can last from 30 minutes to ers tow one net off each several hours. Depths can range from 5 to 700 fathoms side of the vessel. Large (a fathom equals six feet). Bottom trawlers typically fish outriggers are lowered to from 1 to 40 miles offshore. a 60-degree angle to let the The crew hauls in the net by winching in the cables nets out. The nets are either kept on a reel or folded until the doors are back in place and most of the net is on deck. In port, they might be hung from the boom. on the reel. Once the catch is on board, the net is reset Double riggers have a set of doors for each net. The for another tow. Then the fish are separated into deck nets also have chains (tickler chains) attached to the bins (checkers) and put in the hold, where they are iced footrope. These chains drag along the muddy bottom, or refrigerated. It is not unusual to have up to 15 tons stirring the shrimp up off the bottom and into the net. of fish in the hold.

Double-rigged shrimper in operation Outrigger Double-rigged shrimper

Boom Outrigger

Doors Nets Tow cable

Winch Net Hold Door Hopper and sorting machine

2 Getting to Know Oren go ’s Marine Industry On board, the shrimp are emptied from Midwater trawlers are rigged like bot- the net onto a shallow sorting table or tom trawlers but use tall, concave, metal dumped into a temporary storage hopper doors and frequently have more than one and then sorted mechanically. Small fish net reel on board. An overhead A-frame, are removed as the shrimp is conveyed or gantry, on the stern holds one or two to the fish hold, where they are packed in reels. There may even be a third reel near ice. Pacific shrimp are processed onshore the pilot house. through a cooking and peeling process and then shipped fresh or frozen in a process management called individually quick frozen, or IQF. The sorting tray or machine and small mesh Shrimp catches vary according to oceano- distinguish a shrimper from a bottom graphic conditions. The local shrimp dragger or midwater trawler. Double - is one of the cleanest shrimp fisher- gers have large outriggers and two sets of ies in the world, with catch being almost doors. entirely pink shrimp. Fishermen now use reduction devices to virtu- ally eliminate the bycatch of rockfish and midwater trawlers halibut. Midwater trawlers tow a net off the stern When it comes to groundfish, manag- from just above the bottom to just below ers have steadily tightened the allowable ORESU-G-03-007 the surface. They harvest fish traveling quotas to protect the species. The fishery © 2003 by Oregon State in schools, such as Pacific whiting. The is further managed with limited entry per- University fishermen use electronic equipment to find mits, area closures, and gear restrictions. and stay with the fish. The net is trawled a This publication was funded by the shorter time (10 to 30 minutes) than shrimp National Grant or bottom trawlers. One tow may yield 50 College Program of tons of fish. Midwater trawler the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration, under NOAA grant number NA16RG1039 (project number A/ESG-5), and by appropriations made by the Oregon State legislature. The views expressed herein do not necessarily reflect the views of any Gantry of those organizations. Writers: Ginny Goblirsch and Steve Theberge Artist: Herb Goblirsch Reel Editor: Sandy Ridlington Design: Rick Cooper Reel with net Layout: Sandy Ridlington Consultant: Scott McMullen Winch

Stern ramp Hold Door

Getting to KKnow Oren go ’’s CCommercialial FFisheriesisheries 3